1. Field of the Invention
The present invention relates to a small-sized push button switch to be used in various office automation equipment, apparatuses to be mounted in a vehicle, and the like, and in particular, to a push button switch in which a portion of a metal sheet member employed as terminals and fixed contacts is installed in a case through an insertion molding process.
2. Description of the Prior Art
Based on specifications of the projection of terminals (leads), electronic parts can be briefly classified into radial lead electronic parts, axial lead electronic parts, and electronic parts of different shapes.
The radial lead electronic parts are represented by, as shown in FIG. 7, such parts as a capacitor 20 of which leads 20a, 20a are projected in the same direction. The capacitors 20 arranged on a holder sheet 21 by use of an adhesive tape 22 are supplied to an automatic dispenser of radial lead electronic parts so as to be mounted on printed circuit boards.
The axial lead electronic parts are represented by, as shown in FIG. 8, such parts as a resistor 23 of which leads 23a, 23a extend from the body thereof toward the right and left directions. The resistors 23 arranged on holder sheets 21 by use of an adhesive tape 22 are supplied to an automatic dispenser of radial lead electronic parts so as to be similarly mounted or installed on printed circuit boards.
Moreover, the electronic parts of different shapes are represented by, as shown in FIGS. 9-10, parts such as a push button switch 24 of which, for example, four leads 24a project in the respective directions. The push button switches 24 arranged in holding member 25 are supplied to an automatic dispenser of electronic parts of different shapes manufactured specifically for the respective parts of different shapes so they may be similarly mounted on printed circuit boards.
Among the respective automatic inserters of the radial lead electronic parts, axial lead electronic parts, and electronic parts of different shapes described above, the automatic inserter of the radial lead electronic parts is most popular and has a simple structure, whereas the automatic inserter of the parts of different shapes must be manufactured for a dedicated use and hence its cost is increased. Consequently, in a case where the number of parts to be installed in a printed circuit board is small, manual assembly is commonly used for the installation of parts of different shapes, such as the push button switch. In this case, however, the automation line must include manual assembly, resulting in reduced assembly efficiency.